Advanced Configuration And Power Interface (Acpi); System States And Power States; Effects Of Pressing The Power Switch - Intel MS440GX Product Manual

Advanced Configuration and Power Interface (ACPI)

ACPI gives the operating system direct control over the power management and Plug and Play
functions of a computer. ACPI requires an ACPI-aware operating system. ACPI features include:
Plug and Play (including bus and device enumeration) and APM functionality normally
contained in the BIOS
Power management control of individual devices, add-in boards (some add-in boards may
require an ACPI-aware driver), video displays, and hard disk drives
A Soft-off feature that enables the operating system to power off the computer
Support for multiple wake up events (see Table 32)
Support for a front panel power and sleep mode switch. Table 31 describes the system states
based on how long the power switch is pressed, depending on how ACPI is configured with an
ACPI-aware operating system
Table 31. Effects of Pressing the Power Switch
If the system is in this state...
Off
On
On
Sleep

System States and Power States

Under ACPI, the operating system directs all system and device power state transitions. The
operating system puts devices in and out of low-power states based on user preferences and
knowledge of how devices are being used by applications. Devices that are not being used can be
turned off. The operating system uses information from applications and user settings to put the
system as a whole into a low-power state.
...and the power switch is
pressed for
Less than four seconds
Less than four seconds
More than four seconds
Less than four seconds
Using the BIOS Features
...the system enters this state
Power on
Soft off/Suspend
Fail safe power off
Wake up
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